1. Field of the Invention
The present invention relates to an objective lens adapter that is attachably/detachably attached to the distal end of an objective lens to protect a front lens of the objective lens.
This application is based on Japanese Patent Application No. 2008-164638, the content of which is incorporated herein by reference.
2. Description of Related Art
Conventionally, an adapter that is attachably/detachably attached to the distal end of an endoscope insertion unit has been known. By attaching this adapter, the field of view can be changed (for example, refer to Japanese Unexamined Patent Application, Publication No. Sho 56-85324).
However, when attaching an adapter to the distal end of an objective lens in a microscope apparatus for conducting high-precision observation of a minute specimen at a high magnification, it is necessary to bring an optical element into contact with the distal end of the objective lens because the optical element needs to be precisely attached. In this case, in particular, when attaching to an objective lens having a small-diameter distal-end portion in which the diameter of the distal-end portion is extremely small for piercing biological tissue such as brains, to observe an organism in vivo, there is a problem in that the distal-end of the objective lens and the optical element may be damaged if an excessive pressing force is applied to the optical element at the time of attachment.